Geothermal Done Right

Renewable Energy

Steve Stackhouse

Oconto Electric CO-OP

MREC

What will be discussed in this session?

Key applications, components and challenges of every

geothermal system.

Types of energy extraction loops and installation methods.

System performance vs alternatives.

Financial Evaluation “Do the Math”.

Example of installation with Geothermal.

Where is the future of geothermal.

Consumer Research 2015

Department of Energy Goal

Key Components to Achieve a Successful

Geothermal System

• Geothermal Heat Pump

• Energy Delivery System

• Geothermal Earth Loop

• Liquid Loop Heat-Exchange Medium

• Qualified Installing Professional

• Qualified Designing Professional

Interesting Facts

According to the Environmental Protection Agency (EPA), GeoExchange technology is the most energy-efficient, environmentally-clean and cost-effective space conditioning

system available.

Federal Tax Credits (residential) currently in place allows for a 30% tax credit through

December 2016.

“Geothermal”-- Heat from the earth

Normal earth temperatures

Earth absorbs 47% of the sun’s energy

that reaches it

Available everywhere

Not associated with geysers

What Is Geothermal Energy?

Sun

The earth can absorb nearly half of the sun’s energy. The ground stays a

relatively constant temperature through the seasons, able to absorb the

rejected heat in summer and release this heat stored back in the winter.

Earth Temperatures

• A few feet below the surface, earth

temperatures remain relatively constant

and moderate.

• Ground temperatures are much milder

than average monthly air temperatures.

During the heating season, the earth

serves as a heat Source. (HE - Heat of

extraction)

During the cooling season, the earth

serves as a heat Sink. (HR - Heat of

rejection)

Energy Source

Ground Source Heat Pumps

Heat pumps “move” energy from one location to another, instead of creating heat by burning fossil fuels, such as a gas furnace does. -- (like your refrigerator). Geothermal Heat Pumps use the earth or well water to provide heating, cooling and hot water for your home.

The heat moves through a liquid medium

inside a loop system (Closed Loop) or through well-water (Open Loop)

Ground Source Heat Pumps

Heating

Operation

HEATING

COOLING

The Second Law of Thermodynamics

Energy (heat) flows spontaneously

from an area of high concentration (hot

body) to an area of low concentration

(cold body).

Always hot to cold, never cold to hot

Cooling is actually the removal of

heat

Loop System Materials

High Density Polyethylene

Flexible

Heat Fusion Capable

Socket

Butt

Loop System Types

Closed Loop (w/ antifreeze)

Horizontal

Vertical

Pond

Open Loop

Well Water

Horizontal and Vertical

Horizontal Racetrack Design

Individual Channel Loop Installation

Vertical Bohr Installation

U-BEND at Bottom of Bohr

Grout inserted from bottom to the top of Bohr.

Directional Bohr Loop Installation

Pond Loop

Requires minimum of ½ acre private land

9 feet deep at most shallow season of the year

HDPE Loop Pipe Benefits

• High density polyethylene pipe (life expectancy of over 200 years)

• Does not rust, rot, or corrode • All connections are made by heat

fusion • 50 Year No Leak Pipe warranty

Equipment Performance Ratings

ARI has designated the efficiency ratings for water-to-air

heat pumps as:

Energy Efficiency Ratio (EER)

EER = BTU output divided by power watt input

For cooling operation under steady state test

conditions

Coefficient of Performance (COP)

COP = BTU output divided by BTU input

For heating operation under steady state test

conditions

Cooling Performance Ratings

Geothermal 17-41 EER

Air Source Heat Pump 10-15 EER

Air Conditioner 10-15 EER

Heating Performance Ratings

Geothermal (ground source) 3.5-6.0 COP

Air Source Heat Pump 1.8-2.0 COP

Fossil Fuel Furnace 0.80-0.95 COP

Electric Furnace/Baseboard/Ceiling Cable

1.00 COP

2011 SCWBA Parade of Homes

Total Sq. Feet = 4,949

-Heating load = 63,663Btuh

-Cooling load = 41,306 Btuh

Geothermal Water to Air 5 ton system

- 3 thermostat control zoning

- Domestic hot water desuperheater

Geothermal Done Right !

Requirements of HVAC Designer / Contractors:

1. ACCA Manual J (or Automated) Load Calculations

Appliance Heat Gains

Solar Heat Gain / Loss

Occupancy Heat Gain

Infiltration Rates and Building Envelope

2. ACCA Manual S (or Automated) Duct Calculations

Duct gain or Loss

Energy Flow and Distribution

Geothermal has come a long

way from the days of

ignition and combustion.

With Geothermal both

comfort and efficiency are

built directly in.

Questions?